The CBI was plunged into controversy in recent weeks when it registered as an official supporter of the No campaign with the Electoral Commission. It provoked a storm of protest and the body later withdrew this registration, claiming a mistake had been made.

Sir Mike will tell its annual dinner tonight that the body will continue to raise economic questions on the referendum issue. “The decision on independence is, of course, for the Scottish people,” he will say. “But the effects of the decision will be felt by others, including businesses – not just in Scotland but in Wales, Northern Ireland and England.

“The CBI has the right and duty to ask the difficult questions about issues which affect our members’ interests and this country’s economic future.

“Ultimately, because of the range of unknown and unforeseen consequences of independence, it is difficult to see how independence would be better for investment and for jobs. The case has not been made that an independent Scotland would be better for our economy.”

But a spokeswoman for the pro-independence Business for Scotland group said: “The CBI’s reputation has been permanently damaged by its No campaign, which has led to the withdrawal of membership by more than 20 Scottish organisations.

“As CBI membership declines, that in Business for Scotland is increasing by the day and now stands at just under 2,000 people. This organisation’s growth is clear testament to the fact that more and more businesses here see the opportunities that independence offers them.

“They see that Scotland’s economy will thrive in the hands of a Scottish Government that understands its needs.”